<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>CSS3立方体</title>
    <style>
        .box{
            position: relative;
            width: 600px;
            height: 500px;
            margin: 0 auto;
            border: 1px solid red;
        }
        .page{
            position: absolute;
            top: 100px;
            left: 100px;
            width: 100px;
            height: 100px;
            background: rgba(0,0,0,0.3);
        }
    
    </style>
</head>
<body>
    <div class="box">
        <div class="page page-1"></div>


    </div>
</body>
</html>